In various rotating machines including a compressor, a turbine, or the like, lubricating oil is supplied to a lubrication target portion which includes a bearing supporting a rotating body or the like and requires lubrication. The lubricating oil which has passed through the lubrication target portion is recovered in a drain. However, since a portion of the lubricating oil is stirred by the rotating body which rotates at a high speed in the lubrication target portion, the portion is made to be mist. Even when the misted lubricating oil can be captured by a filter, a strainer, or the like, a portion of the misted lubricating oil may pass through the filter or the strainer.
In addition, in the rotating machine, steam or gas which is working fluid and the lubrication target portion such as a bearing are separated from each other by a separation gas such as N2 gas introduced into the rotating machine.
In this way, the misted lubricating oil or the separation gas existing in the rotating machine is discharged from a vent (funnel) which is provided in the rotating machine. The vent is lengthened so as to cool and liquefy the misted lubricating oil while the misted lubricating oil passes through the vent and extends upward from the rotating machine. When the misted lubricating oil or the separation gas is discharged to the atmosphere, an opening portion of the tip of the vent is set at a high position from the ground surface in order to decrease influences of the misted lubricating oil or the separation gas with respect to the surrounding.
PTL 1 discloses a configuration in which atmosphere discharge pipes connected to a plurality of bearings of a rotary machine are connected to one atmosphere discharge pipe (vent). In this configuration, a lubricating oil component which is discharged from respective bearings through the plurality of atmosphere discharge pipes is discharged to the atmosphere through only one atmosphere discharge pipe.
In addition, PTL 2 discloses a configuration in which an atmosphere discharge pipe is not provided for each rotating device and a suction device and an atmosphere discharge pipe are provided in a lubricating oil tank.